1. Field of the Invention
The present invention pertains broadly to a process for the solvent extraction of polychlorinated organic compounds from porous materials. More particularly, the invention relates to a process for the extraction of hexachlorinated to decachlorinated organic compounds from porous materials, such as concrete, cement, and polymeric materials, such as vinyl ester resins, using a solvent or solvent system.
2. Relevant Art
Organic and chlorinated hydrocarbon organic solvents are known for their ability to remove ink, oils, greases and the like from machinery, metal parts, electronic equipment, printing equipment and the like. Usually cloths are soaked with the solvent, and the grease is removed by manually wiping the equipment. In other applications, small parts, such as electronic parts, are submerged into the solvent from ambient to boiling temperature to remove the undesired greases or oils.
U.S. Pat. No. 3,773,676 discloses the use of a non-flammable mixed solvent system consisting of low- and high-boiling noninflammable halogenated organic, such as, perchloroethylene and a light petroleum solvent such as mineral spirits, which is useful for removing inks, greases, and the like from printing equipment.
Cheek, in U.S. Pat. No. 4,507,155, discloses the use of a cleaning solvent comprising a chlorinated hydrocarbon, a petroleum distillate, and alcohol and ammonia for use in removing a dried printing ink residue from a substrate. Representative chlorinated hydrocarbons described by Cheek include chloroform, carbon tetrachloride, trichloroethane, tetrachloroethane, pentachloroethane, trichloroethylene and perchloroethylene. There is no teaching regarding the level of hexachlorinated organic compounds removed or remaining in the substrate. Also, West German Patent No. DE 3,102,746 and Sovient Union Pat. No. 910,851 are of general interest.
Polymeric structural materials are often found in the equipment used in the manufacture, processing and transportation of solvents. It is known that polymeric materials absorb quantities of chlorinated hydrocarbons, particularly hexachloroethane, during manufacture, transportation and storage. When the level of polychlorobiphenyls (PCB's) is 7 ppm or higher in any material, present environmental regulations in California will not permit it to be disposed of in an economical landfill operation (The level is 50 ppm on a national scale). Since hexachloroethane is less of an environmental problem than are the PCB's the designation for these levels of contaminants is conservative. Further, disposal by incineration or storage on site of, for instance contaminated polymeric material, is very costly.
There are no references disclosing the removal of chlorinated organic compounds from solid materials. It is, therefore, very desirable to have a simple, economical process to remove hazardous chlorinated hydrocarbons from porous materials, such as polymeric materials, so that the porous materials can be further used or disposed of in an environmentally acceptable manner.
It is an object of the present invention to provide an improved method of solvent extraction for removing highly chlorinated organic compounds from polymeric materials.
It is a further object of the present invention to provide a cleaning composition that is easy to handle and safe to use.
These and other objects will become apparent from the following description.